Welcoe and thanks for posting your query to HCM.
During your foreplay you must have injured the hymen
( a thin membrane just inside the vaginal opening). This membrane is a very delicate structure just like a paper and is very vascular too. So even a minor insertion of finger can lead to rupture or injury
of the hymen. Though most commonly hymen ruptures completely during full insertion during intercourse but it is quite common during fore play also when we insert one or two fingers inside vagina. So you and your fiancee should not be worried about the simple problem. The area heals very fast so be happy and tension free.
Hope this information helps you.
Dr Sanjay K Kanodia
MD( Skin & STD